It is known that aging causes the stratum corneum to begin to lose its ability to renew itself through desquamation; in fact, mature skin may take twice as along to be renewed as compared to young skin. Treatments that accelerate the desquamation process of the stratum corneum increase the rate at which new cells of epidermal tissues are formed.
To restore the skin's freshness and youthful appearance, periodically a deep cleansing of the facial skin is needed, to increase epidermal desquamation and to remove the oily particles excreted from the sebaceous glands located in the dermis. These oil glands continuously excrete and channel the sebum from the deep dermis to minute openings at the skin surface. The sebum has a tendency to solidify over the sebaceous orifice, resulting in the formation of hardened plaques favouring the development of acne, cysts, white and black heads.
Skin peels for the treatment of aged or damaged skin have been used by dermatologists for some time. It is known that the outer layers of human skin can be caused to peel by applying special chemical formulations, able to remove dead skin and to wound underlying living skin tissue. Treatment of skin using a chemical peeling agent is typically called “chemical peel”. Chemical peels are performed with chemical peeling agents such as alpha- and beta-hydroxy acids, trichloroacetic acid, phenols, etc. The chemical peeling agent is applied to the skin as aqueous or organic solutions, at an appropriate concentration, for a suitable period. In the chemical peeling the surface dead cells must be either removed or penetrated by the chemical peeling agents that loosen the bonds between dead skin cells and underlying living tissue, stimulating the cells to form new collagen.
Result of the chemical skin peeling is that the underlying layers of skin, now exposed, are relatively free of age lines, superficial wrinkles, acne scarring, dryness, pigment spots, aging spots and acne lesions. In addition, the exposed skin tissue looks more youthful in part, because it is smoother and reflects light more readily, thus rendering a “healthy glow” appearance. Deep chemical peels may cause undesirable skin reactions, such as frosting (whitening due to the denaturation of superficial proteins), rash or redness, on the skin of the wearer. If the wearer has such skin reactions, he or she should immediately discontinue the treatment. In some cases, another agent should be applied to the skin to neutralize the peeling agent.
Chemical peeling can be done in varying degrees of depth, called light, superficial, medium, and deep peels. A light or superficial peel is superficial in effect and produces few or no undesirable side effects, while medium or deep chemical peels produce a moderate to severe wound to the skin, with pain and inflammation. Medium and deep peeling is accomplished by the application of high-concentration peeling agents, either in a single treatment session, or, at most, over a period of repetitive treatments over several days in a professional setting. Deep peeling usually produces redness lasting several days, a large and deep separation of dead skin, and the exposure of deep living skin tissue. The results of medium and deep peeling are not equivalent to the results of light or superficial peels or exfoliation.
Additional steps of the peeling process have been disclosed, such as: before the peeling, the skin is cleaned and degreased applying various chemical agents on the skin; to stop the peeling, the peeling agents are neutralized and/or removed; at the end of the peeling treatment the affected skin is treated topically with a moisturizer or other after-care preparations.
Chemical peels require application of the peeling agent to the skin at an appropriate concentration. Direct application of the chemical peeling agent to the skin has however many problems in conjunction with formulation and application strategy. It tends to produce uncovered portions of the skin or result in uneven applications of the peeling agent. To overcome these problems, the prior art describes the use of bandage pad or a similar patch. Conventional bandage pads designed to stay on the skin for chemical peels have a backing made of fabric with a chemical peeling agent applied thereto.
The prior art doesn't provide univocal data for standardization of the peeling process. Generally, a dermatologist, aesthetician or cosmetologist does not apply skin peeling agents in a uniform way with respect to: the preparatory degreasing, a critical area of variability in the effectiveness and depth of skin penetration achieved by the skin peeling agents; the type of ingredients used and their concentrations; the duration of skin contact with the peeling agents; the degree of abrasiveness employed in the course of treatment; the post-treatment for affected skin.
Different types of peeling treatments or protocols have been described. Various attempts have been made to utilize alpha-hydroxy acids, such as glycolic acid and other compounds in skin care products, as noted in U.S. Pat. Nos. 3,879,537, 3,920,835, 3,984,566, 3,988,470, 4,021,572, 4,105,783, 4,197,316, 4,234,599, 4,246,261, 4,363,815, 4,380,549 and 4,363,815. The peeling agents described in these patents, in addition to the glycolic acid, include citric, glucuronic, alpha-hydroxybutyric, alpha-hydroxy-isobutyric, lactic, malic, mandelic, mucic, pyruvic, galacturonic, beta-phenyllactic, beta-phenylpyruvic, beta-hydroxybutyric, saccharic, tartaric, tartronic acids, glucuronolactone, gluconolactone, methyl pyruvate, ethyl pyruvate. However, glycolic acid is more effective in treating skin conditions, because of its activity in relation to the removal of dead skin layers and moisturizing and on treating live skin. In fact, glycolic acid penetrates the dermal layers better than other alpha hydroxy acids and peeling agents, thanks to its relatively smaller molecular size. Furthermore, glycolic acid acts better at peeling and/or exfoliating skin when used synergistically in combination with relatively low concentrations of acetone. Glycolic acid has been specifically described as an agent to loosen bonds between dead and live skin cell layers, as noted in M. Murad, “A Primer on Glycolic Acid,” March/April, 1993, Dermascope, Dallas, Tex. 75202. However, the use of glycolic acid has been criticized in U.S. Pat. No. 4,294,852, which alleges that the use of certain alcohols in combination with alpha-hydroxy acids permits their use in significantly lower concentration to achieve the same result.
U.S. Pat. Nos. 4,874,361 and 5,166,176 disclose the use of tricholoroacetic acid (TCA) as peeling agent in association with surfactants and emulsifiers which are spread over the affected skin area. The covered skin area is then subjected to ultraviolet radiation. The resulting peel yields a new layer of vibrant, evenly coloured, healthy skin, usually with only a single application.
U.S. Pat. No. 4,608,370 discloses the use of lactic acid, salicylic acid, alcohol and resorcinol administered once in a single application, where the intended effect is expected to occur over a week period for removal of dead skin in what is referred to as “peeling” in a non-irritating manner.
U.S. Pat. No. 5,164,413 teaches the treatment of acne with formulations comprising resorcinol, lactic acid, salicylic acid and ethanol. This treatment has a controlled irritation, so that blemished skin dies after minor irritation and is replaced by healthy, fresh skin in the process known as exfoliation.
Other related preparations for skin treatment include U.S. Pat. No. 4,035,513, U.S. Pat. No. 4,124,720, U.S. Pat. No. 4,195,077, U.S. Pat. No. 4,287,214, U.S. Pat. No. 4,505,925, U.S. Pat. No. 4,695,452, U.S. Pat. No. 4,824,865, U.S. Pat. No. 4,931,591, U.S. Pat. No. 5,110,603, U.S. Pat. No. 5,720,390, U.S. Pat. No. 5,962,4411, U.S. Pat. No. 5,730,991, U.S. Pat. No. 5,728,390, U.S. Pat. No. 5,863,546, U.S. Pat. No. 6,169,110, U.S. Pat. No. 6,521,271, US 20020192253, US 20040039323 and US 20040067243.
Cosmetic applicator pads and/or medicated cleansing pads have been described in use with salicylic acid and alcohol, as noted in U.S. Pat. No. 4,891,228. Other patents relating to cosmetic or medicated applicator pads include U.S. Pat. Nos. 3,706,595 and RE 28,957; U.S. Pat. No. 3,778,341; U.S. Pat. No. 4,341,213; U.S. Pat. No. 4,719,226; U.S. Pat. No. 4,738,848.
Moreover, U.S. Pat. No. 4,514,385 discloses salicylic acid in an anti-acne aqueous gel delivered in a polymer vehicle and U.S. Pat. No. 4,830,854 teaches the use of salicylic acid in a pad for desquamation of skin, epidermal hydration, along with diffuse loosening of a foreign body embedded in the skin.